Search for Λ[over ¯]-Λ Baryon-Number-Violating Oscillations in the Decay J/ψ→pK^{-}Λ[over ¯]+c.c

Area of Science:

• Particle Physics
• High-Energy Physics
• Quantum Mechanics

Background:

• The Standard Model of particle physics describes fundamental particles and forces.
• Hyperons, such as Lambda (Λ) and anti-Lambda (Λ[over ¯]), are baryons containing strange quarks.
• The possibility of oscillations between matter and antimatter particles, like Λ and Λ[over ¯], is a key area of investigation.

Purpose of the Study:

• To conduct the first search for Λ[over ¯]-Λ oscillations.
• To analyze the decay J/ψ → pK⁻Λ[over ¯] + c.c. for evidence of these oscillations.
• To set limits on the oscillation rate and parameter.

Main Methods:

• Analysis of 1.31×10⁹ J/ψ events collected by the BESIII detector.
• Utilizing J/ψ events produced from e⁺e⁻ collisions at a center-of-mass energy of 3.097 GeV.
• Statistical analysis to search for oscillation signals and set upper limits.

Main Results:

• No evidence for Λ[over ¯]-Λ oscillations was observed in the analyzed J/ψ decays.
• An upper limit for the oscillation rate P(Λ) was determined to be less than 4.4×10⁻⁶.
• An upper limit for the oscillation parameter δm_{ΛΛ[over ¯]} was set at less than 3.8×10⁻¹⁸ GeV at the 90% confidence level.

Conclusions:

• The search found no indication of hyperon oscillations.
• The results provide stringent constraints on the Λ[over ¯]-Λ oscillation phenomenon.
• This study contributes to the ongoing exploration of CP violation and matter-antimatter asymmetries in particle physics.